1. Field of the Invention
The invention relates in general to insertion machines for compiling sets of documents and inserting such sets into envelopes, and in particular to an accumulator device having a belt-dampening table and side guides for dampening the oscillating tendencies of the belts when driven at high speeds.
2. Related Art
Belt-driven accumulators are well-known for accumulating sets of documents from a stream of documents fed seriatim thereto. Such accumulators typically include at least two driven belts which engage a document at its upper and lower surface, respectively, shaft-mounted pulleys for directing and driving the belts, two side guides which engage and guide the edges of documents being transported by the belts, a ramp for directing the document upward onto the top of a stack of accumulated documents ("over-accumulation") or downward under a stack of documents ("under-accumulation"), and a sheet-restraining means for preventing the stacked documents from being fed by the belts until all sheets for a particular set have been accumulated.
However, belt-driven ramp accumulators of the prior art have typically had limitations which prevent them from being operated reliably at very high speeds. Such limitations include the inability to operate consistently at certain speeds without jamming due to, e.g., document collisions.